Neuropsychological Assessment for Early Detection and Diagnosis of Dementia: Current Knowledge and New Insights.

Dementia remains an underdiagnosed syndrome, and there is a need to improve the early detection of cognitive decline. This narrative review examines the role of neuropsychological assessment in the characterization of cognitive changes associated with dementia syndrome at different states. The first section describes the early indicators of cognitive decline and the major barriers to their identification. Further, the optimal cognitive screening conditions and the most widely accepted tests are described. The second section analyzes the main differences in cognitive performance between Alzheimer's disease and other subtypes of dementia. Finally, the current challenges of neuropsychological assessment in aging/dementia and future approaches are discussed. Essentially, we find that current research is beginning to uncover early cognitive changes that precede dementia, while continuing to improve and refine the differential diagnosis of neurodegenerative disorders that cause dementia. However, neuropsychology faces several barriers, including the cultural diversity of the populations, a limited implementation in public health systems, and the adaptation to technological advances. Nowadays, neuropsychological assessment plays a fundamental role in characterizing cognitive decline in the different stages of dementia, but more efforts are needed to develop harmonized procedures that facilitate its use in different clinical contexts and research protocols.

A novel abbreviated version of the Luria neuropsychological diagnosis battery: reliability and convergent validity in Spanish older adults.

OBJECTIVE: To estimate the test-retest and inter-rater reliability of the new Spanish abbreviated version of the Luria Neuropsychological Diagnosis (DNA-2) battery for older adults. METHOD: A total of thirty cognitively healthy volunteers were examined in this study. The participants completed a comprehensive standardized assessment, encompassing cognitive and functional performance. Intraclass correlation coefficients (ICC) were used to examine test-retest and inter-rater reliability. One month was allowed between administrations. Furthermore, correlations between Luria DNA-2 (total and domain subscores) and other classical cognitive measures were explored. RESULTS: The test-retest reliability on the overall Luria DNA-2 score was high (ICC= .834, 95% CI [.680, .917], p < .001). Furthermore, the inter-rater reliability for the total score demonstrated an excellent concordance between administrators (ICC= .990, 95% CI [.979, .995], p < .001). Positive and significant correlations were observed between Luria DNA-2 (both total and domain subscores) and the Addenbrooke's Cognitive Examination (ACE-III; ρ = .857, p < .001). CONCLUSIONS: This study supports the adequate reliability of the Luria DNA-2, as an abbreviated neuropsychological battery, for assessing cognitive performance in Spaniards aged 55 years and older. Future studies should continue to explore the psychometric properties of the Luria DNA-2, particularly those related to its diagnostic validity for early detection of cognitive impairment.

Is cognitive reserve associated with the prevention of cognitive decline after stroke? A Systematic review and meta-analysis.

OBJECTIVE: To conduct a systematic review and meta-analyses of the effect of socio-behavioral cognitive reserve (CR) proxies on cognitive decline after stroke. METHOD: Three journal search and indexing databases (PubMed, Scopus and Web of Sciences) were crossed to examine the scientific evidence systematically. In addition, meta-analytic techniques, using mixed-effect methods, were carried out to estimate the impact (pooled effect size) of CR proxies on either dementia incidence or cognitive decline after stroke. RESULTS: Twenty-two studies were included in the systematic revision, whereas nineteen of them were eligible for the meta-analysis. The findings showed that high education is associated with a decreased rate of post-stroke dementia. Moreover, other CR proxies (e.g., occupation, bilingualism or social interaction) demonstrate a protective effect against non-dementia cognitive decline after stroke, although some inconsistencies were found in the literature. Regarding the meta-analysis, occupational attainment and education) showed a protective effect against post-stroke cognitive impairment diagnosis in comparison with a mixed category of different CR proxies. Second, a main cognitive change effect was found, pointing to greater cognitive change after stroke in those with low vs. high CR. CONCLUSIONS: Our findings emphasize that CR may prevent cognitive decline after stroke, but this effect can be modulated by different factors such the CR proxy and individual characteristics such as age or type of lesion. The methodological divergences of the studies (i.e., follow-up intervals, cognitive outcomes) need unification to diminish external sources of variability for predicting rates of cognitive decline after stroke.

Cognitive reserve and brain maintenance in aging and dementia: An integrative review.

This research is an integrative review of scientific evidence differentiating between cognitive reserve (CR) and brain maintenance concepts. Thus, we have examined how CR socio-behavioral proxies (i.e. education, occupational attainment, and leisure activities) may help to cope with age-related cognitive decline and negative consequences of brain pathology. We also analyze lifestyle factors associated with brain maintenance or the relative absence of change in neural resources over time. Medline and Web of Science databases were used for the bibliographic search in the last 20 years. Observational cohort studies were selected to analyze the effect of different CR proxies on cognitive decline, including dementia incidence, whereas studies employing functional neuroimaging (fMRI) were used to display the existence of compensation mechanisms. Besides, structural MRI studies were used to test the association between lifestyle factors and neural changes. Our findings suggest that education, leisure activities, and occupational activity are protective factors against cognitive decline and dementia. Moreover, functional neuroimaging studies have verified the existence of brain networks that may underlie CR. Therefore, CR may be expressed either through a more efficient utilization (neural reserve) of brain networks or the recruitment of additional brain regions (compensation). Finally, lifestyle factors such as abstaining from smoking, lower alcohol consumption, and physical activity contributed to brain maintenance and were associated with the preservation of cognitive function. Advances in multimodal neuroimaging studies, preferably longitudinal design, will allow a better understanding of the neural mechanisms associated with the prevention of cognitive decline and preservation of neural resources in aging.

Education and Literacy as Risk Factors of Dementia after Stroke and Transient Ischemic Attack: NEDICES Study.

BACKGROUND: A protective effect of education on cognitive decline after stroke has been claimed, but evidence from prospective population-based cohorts is very limited. The differential role of literacy and education on dementia after stroke remains unexplored. OBJECTIVE: This research addresses the role of education and literacy in dementia incidence after stroke and transient ischemic attack (TIA). METHODS: 131 participants with stroke or TIA were identified within the population-based NEDICES study (N = 5,278 persons). Participants were fully assessed at baseline (1994-1995) and incident dementia diagnosis was made by expert neurologists (DSM-IV criteria) after a mean follow-up of 3.4 years. Adjusted Cox regression analyses were applied to test the association between education, literacy, and dementia risk. RESULTS: Within the 131 subjects with stroke or TIA, 19 (14%) developed dementia at follow-up. The Cox's regression model (age and sex adjusted) showed that low education (HR = 3.48, 95% CI = 1.28, 9.42, p = 0.014) and literacy (HR = 3.16, 95% CI = 1.08, 9.22, p = 0.035) were significantly associated with a higher dementia risk. Low education was also associated with dementia when main confounders (i.e., cognitive/functional performance) were considered in the Cox's model. However, after including stroke recurrence, only low/null literacy (versus education) remained as significant predictor of dementia. Finally, low/null literacy showed an effect over-and-above education on dementia risk when both factors were introduced in the adjusted Cox's regression. CONCLUSION: These findings underline the importance of literacy to estimate cognitive decline after stroke in low-educated populations.

Ethanol specifically decreases peroxisome proliferator activated receptor beta in B12 oligodendrocyte-like cells.

Peroxisome proliferator activated receptors (PPARs) are nuclear receptors that control important genes involved in lipid metabolism. Their role in nerve cells is uncertain, although anomalous myelination of the corpus callosum has been described in the PPARbeta-null mouse, and abnormalities of this tissue have been documented in fetal alcohol syndrome in humans. We report here that ethanol treatment of B12 oligodendrocyte-like cells induces a concentration- and time-dependent decrease in the mRNA and protein levels of PPARbeta, with no effect on PPARalpha or PPARgamma. The effect on PPARbeta is seen as an increase in mRNA degradation, as assessed by run-off assays, due to a significant decrease in PPARbeta mRNA half-life, with no observed changes in intracellular localization. Our results suggest a possible link between PPARbeta function and ethanol-induced abnormal myelination in oligodendrocytes.